refactor(editor): Bild-Upload/Delete auf asyncFetch (Item H)

RecipeEditor war noch die letzte Stelle im UI, die das
handgeschriebene "if (!res.ok) { alertAction(...) }"-Pattern
benutzte, welches wir in review-fixes-2026-04-18 ueberall sonst
durch asyncFetch() ersetzt hatten.

Netto: -14 Zeilen, konsistenter Fehlermessage-Fallback (body.message
> res.status), eine Import-Zeile weniger (alertAction raus, asyncFetch
rein).

Gate: svelte-check clean, 184/184 Tests, Upload/Delete-Flow per
Hand zu testen beim naechsten Editor-Touch.

Refs docs/superpowers/plans/2026-04-19-post-review-roadmap.md Item H.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/components/RecipeEditor.svelte

@@ -2,7 +2,8 @@
   import { untrack } from 'svelte';
   import { Plus, Trash2, ChevronUp, ChevronDown, ImagePlus, ImageOff } from 'lucide-svelte';
   import type { Recipe, Ingredient, Step } from '$lib/types';
-  import { alertAction, confirmAction } from '$lib/client/confirm.svelte';
+  import { confirmAction } from '$lib/client/confirm.svelte';
+  import { asyncFetch } from '$lib/client/api-fetch-wrapper';
   import { requireOnline } from '$lib/client/require-online';
 
   type Props = {
@@ -48,18 +49,12 @@
     try {
       const fd = new FormData();
       fd.append('file', file);
-      const res = await fetch(`/api/recipes/${recipe.id}/image`, {
-        method: 'POST',
-        body: fd
-      });
-      if (!res.ok) {
-        const body = await res.json().catch(() => ({}));
-        await alertAction({
-          title: 'Upload fehlgeschlagen',
-          message: body.message ?? `HTTP ${res.status}`
-        });
-        return;
-      }
+      const res = await asyncFetch(
+        `/api/recipes/${recipe.id}/image`,
+        { method: 'POST', body: fd },
+        'Upload fehlgeschlagen'
+      );
+      if (!res) return;
       const body = await res.json();
       imagePath = body.image_path;
       onimagechange?.(imagePath);
@@ -80,14 +75,12 @@
     if (!requireOnline('Das Entfernen')) return;
     uploading = true;
     try {
-      const res = await fetch(`/api/recipes/${recipe.id}/image`, { method: 'DELETE' });
-      if (!res.ok) {
-        await alertAction({
-          title: 'Entfernen fehlgeschlagen',
-          message: `HTTP ${res.status}`
-        });
-        return;
-      }
+      const res = await asyncFetch(
+        `/api/recipes/${recipe.id}/image`,
+        { method: 'DELETE' },
+        'Entfernen fehlgeschlagen'
+      );
+      if (!res) return;
       imagePath = null;
       onimagechange?.(null);
     } finally {